Process of producing powdered metallic tungsten or other hexavalent high-fusing-point metals.



PROCESS F PRODUCING POWDERED METALLIC TUNGSTEIN OR OTHER HEXAVALENTUNITED- STATES;

PATENT OFFICE.

WILHEIiM MAJ'ERT, OF IQERLIN, GERMANY.

HIGH-FUSING-POINT METALS.

No Drawing.

Specificatioii of LetterS'PatentII Application filed Apri1 15, 190 '9.Serial No. 490,145..

Patented Jan. 18, 1910.

To all whom it may concern: v Be it known that I, WILHELM MAJERT, asubject of the German Emperor, and resident of Berlin, Germany, havemade certain new and useful Inventions Relating to Processes ofProducing- Powdered Metallic Tungsten or other Hexavalent High-Fusing-Point Metal.

By using the acid salts of tungstic and' molybdic acid or theunsaturated salts of ;.their addition products with phosphoric orboracic acids for instance, phosphoric 3 molybdic acid, boracic tungsticacidand tungstic boraciczacid, from which the metals are reduced, muchmore finely divided me tallic products are obtained which are for thatreason much more suitable for the (Na Mo O,) from which one molecule ofmanufacture of filaments for incandescent lamps, and so forth. Theselamps may be reduced by beating them red hot and conducting hydrogenover them or they may be heated with oxygen or with zinc dust rovducingthe finel divided tungsten or mo yb denum in the orm of a dense powder,together with the incorporated tungstate, molybdate or phosphate.Suitable salts for this vpurpose. are sodium paratungstate (Na, 0,) "orsodium paramolybdate tungsten or molybdenum may be reduced by the.method indicated leaving in the residue the neutral salts sodium tuntate(Na WO or sodium molybdate (N aiMoOQ. This process may be carriedout asindicated in the following illustrative example. 500 partsby-weight of the finely powdered anhydrous sodium paratungstate may becare,-

- fully mixed with 3.5 parts by weight-of lamp black or other suitablefinely divided carbon and heated to redness in a slowly revolving retortof wrought'iron or other suitable 'material until carb'on-dioxid beginsto escape. Thereupon hydrogen, water gas .or methyl alcohol vapor isadmitted until complete reduction 1s efi'ected. "The mass is then cooledslightly while a constant stream of reducing gases P are admitted thenthe sodium tungstate residue is washed with slightly alkaline water andthen alternately treatment being continued of course, until the sodiumtungstate is eliminated from the residue. The metallic tungsten residueis with water acidulated with hydrochlorlc or sulfur-1c acid and thenwith pure water until a neutral reaction occurs,"this' then washed inmethyl or ethyl alcohol and then with benzol and with the lightest ben--zin, portions of which are allowed to remain incorporated with theresidue, producing a plastic mass which may be keptzin tightly closedreceptacles until it is desired to utilize the same. It is inadvisableto dry the watermoistened metallic powder which readily oxidizes in theair, oxidation also occurring when the water has not been completelydisplaced by the alcohol used in the subsequent washin .It s of .courseunderstood that the sodium tungstate in the first wash waters from theresidue may be reconverted into the. acid salt used in this'process bycombining the same with the proper amount of dissolved tungstic acid.

Having described this inventionin connection with a number ofillustrative ingredients, proportions and methods of preparation, to,the detailsof which disclosure the invention is not of'course to belimited, what is claimed as new and what is desired t2 be secured byLetters Patent is set forth in the appended claims.

1. The process of producing powdered metallic tungsten for incandescentfilaments ,WhlCh consists in incorporating approximately five hundredparts by weight of finelypowdered anhydrous sodium paratungstate withthirty-five parts of lamp black, in agiv tating and heat ng the same inan atmosphere of reducing gas comprising hydrogen to form metallictungsten 'andincorpora'ted tungstate and-in' dissolving out the sodiumtugnstate. Y, i I

' 2.- The rocess of producing powdered tungsten or incandescentfilaments which consists in incorporating finely \dividedanhydroussodium paratungstate withpowthe incorporated compound tungstic salts toform metallic eliminating the incorporated tungstate;

5. The process of producing powdered metallic tungsten which consists inreducing tungsten and incorporated tungstate and in ellminating theincorporated tungstate.

6. The process of producing powdered high fusing point hexavalent metalfor incandescent filaments and the like which consists 'in reducingalkali para salts of the metal to form the powdered metal-andincorporated residual salt and in eliminating the incorporated residualsalt.

7. The process of producing powdered high fusing point hexavalent metalwhich consists in reducing a. compound salt of the metal to form thepowdered metal'and incorporated residual salt and in eliminating theresidual salt.

7 WILHELM MAJERT.

Witnesses:

HARRY L. DUNoAiI. JESSIE B. KAY.

